JP2015099274A - Lens driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable downsizing of a device and accurate focus control for detection of a lens position.SOLUTION: A lens driving device 1 comprises: a lens frame member 2; a frame member 3; driving means 4 that includes a first driving member 4A fixed to the lens frame member 2 and a second driving member 4B fixed to the frame member 3 and that drives the lens frame member 2 in an optical axis direction; and an elastic regulating member 5 that elastically regulates the movement of the lens frame member 2 in the optical axis direction. One of the first driving member 4A and the second driving member 4B is a coil 40, and the other of them is a magnet 41. Lens position detecting means 7 is provided for detecting a position of the lens frame member 2 by the detection of a magnetic field of the magnet 41 in a core part 40B of the coil 40.

Description

  The present invention relates to a lens driving device, a camera including the lens driving device, an imaging device, a portable information terminal, an electronic device, and the like.

  An electromagnetically driven lens driving device including a coil and a magnet as driving means is known (see Patent Document 1 below). The lens driving device includes a lens frame member including a lens, a frame member disposed around the lens frame member, and a driving unit disposed between the lens frame member and the frame member. And this drive means has the coil and magnet which the side surface along an optical axis direction is opposingly arranged, and one of a coil and a magnet is fixed to a lens frame member, The other is fixed to the frame member. In addition, such a conventional lens driving device includes an elastic restricting member (plate spring) that elastically restricts movement of the lens frame member including the lens along the optical axis direction. The position in the optical axis direction of the lens is variably adjusted at a position where the elastic force and the driving force of the driving means described above are balanced.

JP 2013-156436 A

  In the conventional lens driving device described above, it is difficult to detect the lens position, and the position of the lens frame member is adjusted by changing the balance position of the driving force by the elastic force of the leaf spring and the control current. For this reason, variations in the elastic force of the leaf springs must be taken into account to some extent, and the focus position is a mechanism that cannot be adjusted later, so that focus control with high accuracy is difficult. On the other hand, it is generally known to use a detection mechanism such as a photo interrupter or a photo reflector to detect the focus position. However, it is difficult to cope with downsizing of the apparatus with these mechanisms. It was.

  This invention makes it an example of a subject to cope with such a problem. That is, it is an object of the present invention to be able to cope with the downsizing of the apparatus and to perform highly accurate focus control by detecting the lens position.

In order to achieve such an object, a lens driving device according to the present invention comprises the following configurations among several inventions described in the specification.
A lens frame member that is movable in the optical axis direction of a lens to be mounted, a frame member that is disposed around the lens frame member and that holds the lens frame member movably, and a first drive that is fixed to the lens frame member And a second driving member fixed to the frame member, a driving means for driving the lens frame member in the optical axis direction, and an elasticity for elastically restricting movement of the lens frame member in the optical axis direction. A restricting member, wherein one of the first driving member and the second driving member is a coil and the other is a magnet, and the magnetic field of the magnet is detected by detecting the magnetic field of the magnet at the core of the coil. A lens driving device comprising lens position detecting means for detecting a position.

It is sectional drawing which shows the lens drive device which concerns on embodiment of this invention. It is explanatory drawing (perspective view) which showed the whole structure of the lens drive device which concerns on embodiment of this invention. It is explanatory drawing (decomposed perspective view) which showed the whole structure of the lens drive device concerning embodiment of this invention. It is explanatory drawing (sectional drawing) which showed the whole structure of the lens drive device which concerns on embodiment of this invention. It is explanatory drawing (perspective view) which showed the mounting state of the lens drive device which concerns on embodiment of this invention. It is explanatory drawing which showed the camera (imaging device) provided with the lens drive device which concerns on embodiment of this invention. It is explanatory drawing which showed the camera portable information terminal provided with the lens drive device which concerns on embodiment of this invention.

  A lens driving device according to an embodiment of the present invention includes a lens frame member, a frame member, a driving unit, and an elastic regulating member. The driving means includes a first driving member fixed to the lens frame member and a second driving member fixed to the frame member, and one of the first driving member and the second driving member is a coil and the other is a magnet. It is. And the lens position detection means which detects the position of a lens frame member by detecting the magnetic field of a magnet in the core part of a coil is provided. According to such a lens driving device, the lens position detection unit is arranged by utilizing the core portion of the coil that is an empty space inside the driving unit. Enables position detection. Further, by providing the lens position detection means, the lens position can be detected and the drive means can be controlled, and even when there is some variation in the elastic force of the elastic regulating member, highly accurate focus control can be performed. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the Z-axis direction indicates the optical axis direction, and directions orthogonal to each other in a plane perpendicular to the optical axis (XY plane) are taken as an X-axis direction and a Y-axis direction. Moreover, in the following figures, the same code | symbol is attached | subjected to the same site | part and some overlapping description is abbreviate | omitted.

  As shown in FIG. 1, the lens driving device 1 includes a lens frame member 2, a frame member 3, and driving means 4. The lens frame member 2 includes a lens mounting opening 20 in which a lens is mounted, and is disposed so as to be movable in the direction of the optical axis Oa of the mounted lens. The frame member 3 is disposed around the lens frame member 2 and holds the lens frame member 2 movably. The drive means 4 includes a first drive member 4A that is fixed to the lens frame member 2 and a second drive member 4B that is fixed to the frame member 3. Here, the first drive member 4A is the magnet 41 and the second drive member 4B is the coil 40. Conversely, the first drive member 4A is the coil 40 and the second drive member 4B is the magnet 41. You can also.

  The driving means 4 has the side surface 40A of the coil 40 and the side surface 41A of the magnet 41 face each other at a set interval, and the lens frame member is driven by the driving force (Lorentz force) generated by passing a current through the coil 40 in the magnetic field of the magnet 41 2 is driven in the direction of the optical axis Oa. That is, the coil 40 is wound in an oval shape having a linear portion along the Y-axis direction, and the aforementioned driving force is applied to the optical axis Oa in the winding direction of the coil 40 and the direction of the linear portion and the magnetic pole arrangement of the magnet 41. It is suitably arranged so as to act in the illustrated Z-axis direction along. In the illustrated example, a yoke (magnetic body) 42 is fixed to the surface of the magnet 41 opposite to the side surface 41A, thereby increasing the magnetic field component along the X direction passing through the coil 40.

  The lens driving device 1 also includes an elastic restriction member 5 (5A, 5B) that elastically restricts movement of the lens frame member 2 in the optical axis Oa direction, and a base member 6 that supports the frame member 3. The elastic regulating member 5 (5A, 5B) is attached to the lens frame member 2 and the frame member 3, and provides an elastic force that presses the lens frame member 2 toward the base member 6. This elastic force increases as the lens frame member 2 moves away from the base member 6. The driving means 4 variably adjusts the position along the optical axis direction of the lens frame member 2 by generating a driving force that balances this elastic force.

  Lens position detection means 7 is provided at the core of the coil 40. The lens position detection means 7 detects the position of the lens frame member 2 by detecting the magnetic field of the magnet 41, and can be configured by a Hall element 70, for example. The lens position detection means 7 detects the distance from the center of the magnet 41 by the change in the magnitude of the magnetic field to be detected. In the illustrated example, the lens position detecting means 7 is provided at the core of the coil 40 fixed to the frame member 3, but the coil 40 is fixed to the lens frame member 2 and the magnet 41 is fixed to the frame member 3. If there is, the lens position detecting means 7 is provided at the core of the coil 40 fixed to the lens frame member 2.

  The lens driving device 1 includes a focus position adjustment unit 72. The focus position adjusting unit 72 is connected to the output terminal 71 of the lens position detecting means 7 and the terminals 12 (12A, 12B) to which both ends of the conductive wire of the coil 40 are connected while the focus signal is input. The drive means 4 is driven by the output of the position detection means 7 and the focus signal, and the energization current of the coil 40 is controlled to adjust the position of the lens frame member 2 to the focus position.

  As shown in the assembly perspective view of FIG. 2 and the exploded perspective view of FIG. 3, the lens driving device 1 can be assembled such that the components are stacked on the base member 6. The base member 6 is provided with an opening 6 </ b> C that is substantially centered on the optical axis of a lens (not shown) attached to the lens frame member 2, and light passing through the opening 6 </ b> C is formed on the back side of the base member 6. Incident on the light receiving surface to be arranged. The base member 6 is formed with a support surface 6S and a reference contact surface 6P at a position protruding in the optical axis direction from the bottom surface 6A. The support surface 6S has a shape corresponding to the planar shape of the frame member 3 supported on the support surface 6S, and is formed at a plurality of locations. All of the surfaces are protruding end surfaces 6B protruding from the bottom surface 6A and the same surface. It is formed on (XY plane). The reference contact surface 6P is formed by a plurality of protruding end surfaces 6B on the same plane protruding in a spot shape from the bottom surface 6A. Further, a plurality of rotation restricting portions 60 are formed so as to protrude from the bottom surface 6A of the base member 6 around the opening 6C.

  The frame member 3 is supported on the pair of support surfaces 6S across the opening 6C of the base member 6 via the outer mounting portion 50A of the elastic regulating member 5B made of the plate-like elastic member 50. The other support surface 6S of the base member 6 supports a pair of coil holders 30 with the opening 6C interposed therebetween. The pair of frame members 3 and the pair of coil holders 30 are fixed so that the coils 40 as the second drive members 4B are opposed to each other. The coil 40 is fixed to the frame member 3 by inserting a protruding portion 3E protruding from the side surface 3D of the frame member 3 into the core portion 40B of the coil 40. A pair of projections 3E are provided, and the lens position detection means 7 (Hall element 70) is installed in the space between the pair of projections 3E. The frame member 3 has a pair of arm portions 3C so that it has a cross-sectional shape that is unlikely to be inclined or deformed, and supports the coil 40 while keeping the distance between the coil 40 and the magnet 41 constant.

  The elastic regulating member 5B includes a pair of left and right outer mounting portions 50A, a central inner mounting portion 50B, and an elastic deformation portion 50C that connects between them, and a positioning projection on the support surface 6S in the positioning hole 50A1 in the outer mounting portion 50A. By inserting 6D and placing and fixing the end surface 3B of the frame member 3 on the support surface 6S via the outer attachment portion 50A, the left and right outer attachment portions 50A are fixed to the support surface 6S of the base member 6. One end 2B of the lens frame member 2 is attached to the inner attachment portion 50B of the elastic regulating member 5B. At this time, the attachment member 51 is attached to the end portion 2B of the lens frame member 2 with the inner attachment portion 50B interposed therebetween.

  A pair of outer mounting portions 50A of an elastic regulating member 5A composed of a plate-like elastic member 50 is supported on the end surfaces 3A of the pair of frame members 3 (the elastic regulating member 5A is also a pair of left and right like the elastic regulating member 5B). 50 A of outer side attaching parts, the inner side attaching part 50B of the center, and the elastic deformation part 50C which connects between them are provided. The left and right outer mounting portions 50A of the elastic regulating member 5A are fixed to the end surfaces 3A of the pair of frame members 3 by placing the outer mounting portion 50A of the elastic regulating member 5A on the end surface 3A and pressing and fixing it with the pressing member 52. . At this time, the positioning protrusion 3F on the end surface 3A is inserted into the positioning hole 50A1 of the outer mounting portion 50A and the positioning hole 52A of the pressing member 52. The other end 2A of the lens frame member 2 is attached to the inner attachment portion 50B of the elastic restriction member 5A. At this time, the attachment member 53 is attached to the end portion 2A of the lens frame member 2 with the inner attachment portion 50B interposed therebetween.

  The lens frame member 2 has a protrusion 22 on its side surface 2C, and is attached so that the magnet 41 as the first drive member 4A faces the coil 40 as the second drive member 4B between the pair of protrusions 22. It has been. Here, as the driving means 4, four sets of coils 40 and magnets 41 are provided around the optical axis of the lens frame member 2, but the two sets of coils 40 and magnets 41 arranged along the Y-axis direction shown in the figure are It can be omitted as necessary. In that case, since the support surface 6S for supporting the coil holder 30 can be omitted, the space occupied by the base member 6 can be saved.

  FIG. 2 shows an assembled state with the shield cover 14 removed. The base member 6 is provided with two terminal lead portions 61 in the vicinity of the outer peripheral edge thereof, and the terminals 12 (12A, 12B) are attached to the terminal lead portions 61 via the insulating members 13, respectively. The plurality of coils 40 is constituted by a continuous conducting wire, one end of which is connected to the terminal 12A and the other end is connected to the terminal 12B.

  In a non-energized state where no current flows through the coil 40, the lens frame member 2 is pressed (pressurized) toward the base member 6 by the elastic deformation portions 50C of the elastic regulating members 5A and 5B. The reference end surface 2S is in contact with the reference contact surface 6P of the base member 6 to maintain a stable state. In order to apply such pressure, a lens to which the inner attachment portion 50B of the elastic restriction member 5B is attached to the height in the optical axis direction of the support surface 6S on which the outer attachment portion 50A of the elastic restriction member 5B is supported. The height of the reference contact surface 6P is set so that the height in the optical axis direction of the end 2B of the frame member 2 is increased. At this time, by setting the reference end surface 2S and the reference contact surface 6P as surfaces perpendicular to the optical axis of the lens, the elastic restricting members 5A and 5B are not deformed with respect to the optical axis. The elastic force symmetrical to the optical axis can be continuously applied to the lens frame member 2.

  FIG. 4 is an explanatory view (cross-sectional view) showing the extended state of the lens frame member. When a drive signal is sent to the terminals 12 (12A, 12B) and a current flows through the coil 40, the lens frame member 2 whose movement is restricted by the elastic restriction members 5A, 5B is driven by the drive means 4 as shown in the figure. It moves away from the base member 6 along the optical axis direction by force, and the position of the lens frame member 2 is maintained where the driving force of the driving means 4 and the elastic force increased by the deformation of the elastic restricting members 5A and 5B balance. Is done. In this way, by controlling the driving force of the driving means 4, it is possible to arbitrarily adjust the position of the lens frame member 2 along the optical axis direction.

  FIG. 5 shows a mounted state of the lens driving device. The lens driving device 1 described above is provided on the circuit board 17 on which the image sensor is mounted, and the terminals 12A and 12B drawn from the base member 6 are connected to the connection terminals 17A and 17B of the circuit board 17 by soldering or the like. . The above-described focus position adjustment unit 72 is mounted on the circuit board 17, and the output terminal 71 of the lens position detection unit 7 is also connected to the circuit board 17.

  The outer peripheral end of the shield cover 14 is placed on the cover mounting portion 6 </ b> R provided on the outer peripheral edge of the base member 6. The shield cover 14 is disposed so as to cover the driving means 4 (first driving member 4A, second driving member 4B) and the lens frame member 2 side (support surface 6S side) of the terminals 12A, 12B, and the top plate portion thereof is covered. Is formed with an opening 14A for exposing the lens barrel 21 mounted in the lens mounting opening 20 of the lens frame member 2. By providing such a shield cover 14, it is possible to effectively suppress the radiation of electromagnetic noise emitted from the driving means 4.

  6 and 7 show examples of electronic devices including a lens driving device. As shown in FIG. 6, the lens driving device 1 is attached to an optical device or an electronic device having a condensing, imaging function, or imaging function, such as a camera 100 or an imaging device 200. Further, as shown in FIG. 7, the lens driving device 1 is attached to a portable information terminal 300 (such as a mobile phone, a smartphone, a tablet PC, a notebook PC) having a condensing, imaging function, or imaging function.

  In an optical device or an electronic device (such as the camera 100, the imaging device 200, and the portable information terminal 300) provided with the lens driving device 1, the lens driving device 1 includes the lens position detection unit 7 in the core portion 40 </ b> B of the coil 40. Thus, it is possible to perform focus control with high accuracy by detecting the lens position while realizing miniaturization. In addition, since the outer shell is covered with the base member 6 and the shield cover 14 which are conductive members, it is possible to suppress external radiation of electromagnetic noise, so that the electronic components disposed around the base can be stably operated. be able to.

  Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration of the present invention is not limited to these embodiments, and the design does not depart from the gist of the present invention. Any change or the like is included in the present invention. In addition, the above-described embodiments can be combined by utilizing each other's technology as long as there is no particular contradiction or problem in the purpose and configuration.

1: Lens drive device;
100: Camera; 200: Imaging device; 300: Portable information terminal;
2: lens frame member; 2A, 2B: end; 2C: side surface; 2S: reference end surface;
20: Lens mounting opening; 21: Lens barrel; 22: Projection;
3: Frame member; 3A, 3B: End face; 3C: Arm part; 3D: Side face;
3E: protrusion part; 3F: positioning protrusion;
30: Coil holder;
4: drive means; 4A: first drive member; 4B: second drive member;
40: Coil; 40A: Side surface; 40B: Core part;
41: Magnet; 41A: Side surface; 42: Yoke;
12 (12A, 12B): terminal; 13: insulating member;
14: Shield cover; 14A: Opening;
17: Circuit board; 17A, 17B: Connection terminal;
5, 5A, 5B: elastic regulating member;
50: plate-like elastic member; 50A: outer mounting portion; 50A1: positioning hole;
50B: inner mounting portion; 50C: elastic deformation portion;
6: Base member;
7: Lens position detecting means; 71: Output terminal, 72: Focus position adjusting unit

Claims (6)

A lens frame member movable in the optical axis direction of the lens to be mounted;
A frame member disposed around the lens frame member and holding the lens frame member movably;
A first driving member fixed to the lens frame member and a second driving member fixed to the frame member, and driving means for driving the lens frame member in the optical axis direction;
An elastic restriction member that elastically restricts movement of the lens frame member in the optical axis direction;
One of the first drive member and the second drive member is a coil and the other is a magnet;
A lens driving device comprising lens position detecting means for detecting a position of the lens frame member by detecting a magnetic field of the magnet at a core of the coil.   2. The lens driving device according to claim 1, further comprising a focus position adjusting unit configured to drive the driving unit based on an output of the lens position detecting unit and a focus signal to adjust the position of the lens frame member to a focus position.   The lens driving device according to claim 1, wherein the lens position detection unit is configured by a Hall element.   The camera provided with the lens drive device of any one of Claims 1-3.   The imaging device provided with the lens drive device of any one of Claims 1-3.   The portable information terminal provided with the lens drive device of any one of Claims 1-3.

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